Ulf Culemann is gratefully acknowledged for his contribution to the material.

Dankward Höntzsch is gratefully acknowledged for revision of the external fixation treatment options (2016, with Steve Krikler as editorial consultant).

The authors and editor of the pelvic ring module gratefully acknowledge and recommend Fractures of the Pelvis and Acetabulum, by Marvin Tile, and colleagues. The fourth edition of Tile’s original book was published in March 2015 by the AO Foundation and distributed by Georg Thieme Verlag. Volume 1, The Pelvic Ring, Co-edited by Tile, James Kellam, and Mark Vrahas, is a lucid and comprehensive summary of up-to-date knowledge of pelvic ring injuries.